Officials find new hole in Indiana Dunes

August 14, 2013|By Ellen Jean Hirst | Tribune reporter

Using a Ground Penetrating Radar machine and a special GPS, EPA investigators scan the sand dunes where the boy was swallowed at Mt. Baldy in the Indiana Lakeshore National Park. (Nancy Stone, Chicago Tribune)

Investigators have been using ground-penetrating radar to peer beneath the surface of an Indiana sand dune this week — but they didn't need the $30,000 piece of equipment to spot a second hole not far from the one that swallowed a 6-year-old boy in July.

Geologists have said the holes should not be able to form in dunes, but the new 10-inch-wide hole that was at least 5 feet deep on Mount Baldy was clearly visible to the naked eye, according to Bruce Rowe, a spokesman for the Indiana Dunes National Lakeshore. The mysterious hole was about 100 yards east of where NathanWoessner,of Sterling, Ill., fell into a hole July 12 at about the same height — halfway up the 126-foot dune.

"The very top of it has some sand that has sloughed down into the hole a couple of inches, but below those couple of inches, the hole is almost completely round," Rowe said. "As they were walking along, heading up their next transect for the radar to go down, they literally walked up and saw it."

On Monday, the U.S. Environmental Protection Agency brought in ground-penetrating radar and specialized GPS equipment to take pictures 30 feet beneath the surface of the dune. They hoped to get a glimpse into what might be causing the holes to form.

On Wednesday, new equipment was brought to Mount Baldy, near Michigan City, Ind., to collect sand samples from varying depths in and beyond the new hole. The EPA and the National Park Service hope to determine how long the sand has been in that position and search for debris — such as rotting tree material — to analyze.

The leading theory so far has been that a rotting tree could have created the hole.

"I think the fact that we found another hole intact allows the scientists to truly study it to get a better idea of whether the tree theory is really the correct one," Rowe said. "In that sense, it's great that we found another hole."

Mount Baldy has been shifting rapidly away from the lake — 10 to 15 feet each year — burying the old terrain with new, loose sand. Alan Arbogast, a sand dune expert at Michigan State University, said it's possible that soil buried in the dune from long-ago periods when the dune was covered in vegetation could have provided enough stability for a hole to be preserved.

"Those soils are a little more resistant — they maintain their integrity, they hold the sand together a little bit better than an unaltered sand," Arbogast said. "Toward the top of the Indiana Dunes, there's a particularly well-developed soil that's buried for the most part, but it's conceivable in my mind that this hole is somehow related to that soil."

Still, what caused the hole — whether a tree rotted over time beneath the surface or a group of kids dug a tunnel into the dune — is pure speculation, Arbogast said.

The EPA's findings on what caused these natural phenomena at Mount Baldy could have implications for moving sand dunes across the globe.

The discovery of the second hole could also help determine how Nathan might have been able to breathe as he waited for rescuers while buried 11 feet below the surface. Doctors said Nathan had to have had some way to breathe or he would not have survived for the nearly four hours he was trapped.